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Herbicide resistant broad-leaved weeds:research required to address policy needs - PS2709

Description
Companies making submissions to PSD (Pesticides Safety Directorate) for registration, or re-registration, of herbicides are required to consider the risk that resistance poses to their active ingredients and, if appropriated, propose a resistance management strategy. For PSD to properly evaluate such strategies, data are required to design, test and validate the resistance management strategies proposed by registrants, and to provide a comparative assessment of different assumptions, so that resistance risk profiles can be formulated. Little research on herbicide-resistant broad-leaved weeds has been undertaken in the UK in recent years so there is a lack of independent data on which to judge the validity of proposed resistance management strategies. There is also concern about resistance developing in the horticultural, industrial and amenity sectors where virtually no recent information is available.

The proposed research aims to support regulatory decision-making by helping PSD in its assessment of applicant’s herbicide resistance management strategies, and in its targeting of future data requirements. In addition, the research should contribute to the development of policy on registration requirements and labelling. PSD supports research that addresses regulatory needs rather than control or farmer issues. Thus the primary user of the outputs should be PSD, although the production and publication of information which is relevant to assist herbicide suppliers and users combat resistance is compatible with PSD’s and national policy for more sustainable use of herbicides.

The general objective of the proposed research is: To gain a better understanding of the present and future risks posed by herbicide-resistant broad-leaved weeds in the UK, in order to help regulators formulate what they require from companies in relation to resistance mitigation strategies for both new, and existing active ingredients.
To achieve the general objective, five specific objectives are proposed:

1. To review the current status of herbicide-resistance in broad-leaved weeds worldwide in relation to their population biology, ‘weediness’ and response to herbicides, in order to help predict which species are likely to evolve resistance in the UK in the agricultural, horticultural, industrial and amenity sectors.
2. To determine the resistance characteristics of resistant chickweed and poppy populations in order to understand the extent of cross-resistance to herbicides with the same, and different, modes of action and the consequential impact on management strategies.
3. To determine the biochemical and molecular basis of resistance in broad-leaved weeds in the UK in order to facilitate the development of diagnostic tools for the detection and characterisation of resistance.
4. To maintain a “watching brief” on potential new cases of herbicide-resistance and, if appropriate, develop new testing methodologies and procedures so that the extent of any problems can be better quantified.
5. To undertake technology transfer initiatives to inform suppliers and users of herbicides in the agricultural, horticultural, industrial and amenity sectors of the risks posed by herbicide-resistance and to promote appropriate prevention and management strategies.

Section 7c of the full proposal details the approaches and research plans proposed for each of the five specific objectives. These involve an integrated combination of field, outdoor container, glasshouse and laboratory work. The methodologies have been used successfully in previous studies into herbicide-resistant grass-weeds and should be adaptable for studies on broad-leaved weeds.
Objective
General objective: To gain a better understanding of the present and future risks posed by herbicide-resistant broad-leaved weeds in the UK, in order to help regulators formulate what they require from companies in relation to resistance mitigation strategies for both new, and existing active ingredients.

Specific objectives

1. To review the current status of herbicide-resistance in broad-leaved weeds worldwide in relation to their population biology, ‘weediness’ and response to herbicides, in order to help predict which species are likely to evolve resistance in the UK in the agricultural, horticultural, industrial and amenity sectors.
2. To determine the resistance characteristics of resistant chickweed and poppy populations in order to understand the extent of cross-resistance to herbicides with the same, and different, modes of action and the consequential impact on management strategies.
3. To determine the biochemical and molecular basis of resistance in broad-leaved weeds in the UK in order to facilitate the development of diagnostic tools for the detection and characterisation of resistance.
4. To maintain a “watching brief” on potential new cases of herbicide-resistance and, if appropriate, develop new testing methodologies and procedures so that the extent of any problems can be better quantified.
5. To undertake technology transfer initiatives to inform suppliers and users of herbicides in the agricultural, horticultural, industrial and amenity sectors of the risks posed by herbicide-resistance and to promote appropriate prevention and management strategies.

Project Documents
• Final Report - SID5A : Herbicide resistant broad leaved weeds:research required to address policy needs   (434k)
Time-Scale and Cost
From: 2006

To: 2008

Cost: £397,057
Contractor / Funded Organisations
Rothamsted Research (BBSRC)
Keywords
Amenity              
Arable              
Herbicide use              
Horticulture              
Pest and Weed Control              
Pesticide use              
Pesticides              
Plants and Animals              
Resistance              
Weed Control              
Weeds              
Fields of Study
Pesticide Safety